Latch-in relay



Nov. 14, 1950 P. F. FERRY 2,530,194

LATCH-IN RELAY Filed Feb. 24, 1947 fig 23 gmmm Paul Ferry Patented Nov. 14, 1950 2,53%,iti

UNITED STATES PATENT OFFICE 4 Claims.

- The present invention relates to electrical relays of the latching-in type which has for its main object to lower the required operating current for such relays, so that, whereas commercial latching-in relays at the present time require an operating current of about 100 milliamperes, my relay can be made to operate on a current of as little as milliamperes.

One object of my invention is concerned with the construction of a latching-in relay, which is much less complicated in mechanical design than the present types of latching-in relays and can therefore be produced at a lower cost. My invention provides a latching-in relay which is electrically and mechanically more efiicient than the present types and at the-same time is free from functional and maintenance troubles.

A further object of my invention is to provide a relay of the latching-in type, the principle of which'may be applied to the actuation of several it different kinds of electrical switching means either singly or in multiple arrangement. The switching means referred to above are conventionally known as the open contact, the mercury tilt or the mercury plunger, the "tuned capacitor or inductor" and the so called toggle arm and snap switches.

A still further object of my invention is to provide an electrical relay of the latching-in type which, by a simple dynamical expedient, translates a small motion, derived from energizing my relay, into a relatively large motion, which enables a large and adjustable angle of throw to be achieved for actuating, for example, mercury tilt switches or high-voltage open contact switches.

When used with vacuum tubes, my relay has the important advantage of low current requirement. Since my latching-in relay operates on' as little as 5 milliamperes, it can be used to a special advantage in circuits with cold cathode gas discharge tubes, which have a maximum current rating of less, generally, than 25 .milliamperes.

These and other objects and advantages of my invention will be made clear in the subjoined description with the aidof the attached drawings, wherein:

Figure 1 is a frontal elevation of a possible embodiment of my invention;

Figure 2 is a Wiring diagram for the invention showing switching means of the mercury tilt typ I Figure 3 is a second wiring diagram using an "open contact type of switching means wherein ill a structural part of the relay acts as the common contact member of the switching means.

In the drawing reference numeral I8 denotes a stand or base with. a pair of upstanding arms or posts I I, I Ia which are firmly connected at the top by a bridge member I2, near each end of Which adjacent the posts I I, Ila is pivoted at I3 and I3a, armatures I4, Ida each of which is held in open position by tension springs I 5, which position is outwardly limited, by adjustable stop screws I6, Ilia carried, one on each of the upstanding posts II, I In.

Under the bridge I2 is suspended a polepiece I7, I'Ia the coils l8'of which are connected in an electrical circuit 26 which may carry either A. C. or D. C. Downwardly extendinghamrners or hooked ends I9, Ita are provided, one on each of the armatures I I, I la. These hammers have their ends W and X spaced apart in order to permit a rocking lever to swing into contact with one or the other of the armature hammers at W and X. This lever 20 is pivoted at 2I in the middle of the stand, or base I0, and carries on it a mercury tilt switch 22 having leads 23, 23a.

In Figure 2 is shown a wiring diagram for the latching-in relay using a mercury tilting switch 22. The apparatus to be operated is here dea noted by numeral 25 and is in the circuit 26a which is in parallel with circuit 26, which carries either A. C. or D. C. as stated. A push button or actuating switch 21 is indicated to close the circuit 26, in which are the coils I8. Two positions of the lever 28 are shown by full and dotted lines.

The operation of my latching-in relay is as follows: When the coils I8 are energized upon closing the circuit 26 by the push button 21, both armatures I4 and Ida swinging about pivots I3, I3a are respectively pulled in against the poles I I, I'Ia. This causes the hammer I9, at point W, to impel the rocking lever 20 to swing on its pivot 2I, from its position at W, in full lines to that shown in dotted lines into contact with hammer I9a at X and held there by gravity.

Since the tilt switch 22 is carried on the lever tact for the switching means. The parts are all the same as first described, but the rocking lever 20, the center of gravity of which lies above the pivot point 2|, tends to make electrical connection with one or the other of points W or X of the hammers depending on which side of the perpendicular thru the pivot 2|, the levers center of gravity lies at the time.

To obtain the advantages of snap-switch operation, it is only necessary to fasten the lever 20 to the toggle actuating arm of a conventional snap-switch, or to make such toggle arm integral with lever 20 and the snap-switch mechanism.

In the circuit 31 is connected one apparatus 29 to be operated by this relay to the left of the pivot 2| and another 30 to the right thereof. By so called pig tail wiring from point 28, the lever 20 connects to points 32 and 33 in the circuit 3|.

The operation of my latching-in relay with the open contact switch is similar to that described in relation to the mercury tilt switch.

I have found that the dynamical characteristics of the operation of my latching-in relay are governed, in part, by the existence or non-existence of a fixed mechanical gap between lever 2c and its corresponding hammers l9 and I 9a. The fixed gap may be maintained as herein shown by some conventional means such as a mechanical limiting stop or stud.

This prefixed gap is provided by a pair of set screws 34, 34a, threaded in the upper ends of posts 35, 35a, fixed one on each side of the rocking lever 20 on the base Ii). These screws 35, 36a are set to contact with the sides of the rocking lever so as to limit its throw right and left and not touch either hammer E9 or lfia.

The effect of a prefixed mechanical gap at point W and/or X will become clear'when it is taken into consideration that the movement of lever 2|] will differ by whether it is struck or pushed from its original position of rest. If it is assumed that the time necessary to throw the lever 29 from one point to another is longer when no mechanical gap exists, than when a gap does exist, then it is possible to vary the switching time sequence of switch 22 by allowing a gap at one point but not'at the other. For example, if a mechanical gap should exist at point W but not at point X, and if the switching circuit were in the off position at point W and in the on position at point X, then, by energizing my relay, the switching circuit would close quickly, whereas, by deenergizing and then reenergizing my relay, the switching circuit would open more slowly. Such differential action is desirable in some types of electrical circuits.

A further value of the mechanical gap is found in the following explanation: When the relay is in the deenergized position, the magnetic gaps between armatures I4, Ma and corresponding poles or polepieces I1, I 1a are at their widest and, therefore, a given amount of electrical energy expended in the electro-magnet coils will produce a lesser tractive effort on the armatures than when the magnetic gaps are narrower. This width of magnetic gap is compensated for, in part, by allowing a set mechanical gap to exist at points W and X thereby reducing the effective mass of the armatures by relieving them of the additional mass and inertia of the lever 29 and attached switching means 22 at the instant when the tractive elfort of the electro-magnet coils is at its minimum.

Therefore, the optimum condition of operation.

of the relay may be attained by adjustment of one or all of several variables; namely, the tension of springs 15, the magnetic gaps between armatures l4 and Ma and the poles of the polepieces 11, Ha the weight and length from fulcrum 2| of lever 20, the magnitude of the angle thru which lever 20 travels from its position at point W to point X, and reverse, the fact of whether or not a predetermined fixed gap existed between lever 20 and points W and/ or X.

From inspection of Figures 1, 2, and 3, it may also be seen that the high friction drag mechanisms, such-as ratchets, dogs and cams, which are employed in conventional latching-in relays, are avoided by my invention.

It is to be understood that the invention as herein disclosed may be varied from the details described and shown without departure from the spirit of the subjoined claims.

I claim as my invention:

1. A latching-in relay comprising a base, a pair of upstanding posts thereon, a bridge connecting the upper ends of the posts, an electromagnet coil mounted upon the bridge and having two end pole pieces, an armature pivotally suspended from the bridge adjacent to each pole piece, said armatures having upstanding ends, spring means coupling said ends and normally urging oscillation of'the armatures away from the adjacent pole pieces, a pivotal support disposed upon the base beneath the coil, a lever mounted upon said pivotal support for rocking movement, said lever being directed upwardly and adapted for connection with a circuit controlling unit whereby oscillation of the lever in one direction opens the circuit controlled by said unit and oscillation in the opposite direction closes the same, a pair of resilient elements carried by the armatures and extending downwardly and inwardly and having an end opposed-relation, the upper end of said lever being positioned between the opposed ends of said depending members, the'alternate energization of the coil actuating the armatures to effect movement of the lever first in one direction and then in the other by the engagement of the'said opposed ends ofthe depending members with the lever, and means at-opposite'sides of the lever for varying the extent of oscillation of the same.

2. A latching-in relay of the character described in claim 1, with movement limiting screws carried by said posts each adjacent to an armae ture and adapted to limit the swinging movement of the armature outwardlyfrom its pole piece,

3. A latching-in relay of the character de-' scribed in claim 1, wherein said means for limiting the oscillatory movement of the lever comprises a pair of short post members upstanding beneath the hanging-members and between which the lever is mounted, and-a'pair of screws each carried by one ofthe last mentioned posts in the path of swinging movement of the lever for controlling the extent of such swinging move ment. V

4. A latching-in relay comprising abase with a pairof upstanding posts carrying a bridgemember between them, a magnet spool carried by said bridge member and" having two opposite pole pieces, an armature oscillatably supported on said 5 ducting rocking lever in the space between the striking members with its center of gravity above the pivot axis and adapted to selectively electrically connect with said striker members for alternately conducting current to electrically operated elements.

PAUL F. FERRY.

REFERENCES CITED The following references are of record in the file of this patent:

Number Number 15 783,822

France Apr. 15, 1935 

